A digital subscriber line (xDSL, Digital Subscriber Line) technology is a widely applied broadband access technology at present and supports Internet access of hundred millions of users around the world. There are a huge number of xDSL access devices and the annual power consumption of the xDSL access devices is quite huge. Not only carriers need to pay for huge operating costs every year, but also there are many carbon dioxide emissions, aggravating greenhouse effect and deteriorating the environment.
At present, to optimize a line transmit power of a user port on an xDSL subscriber board (also called board or line card), there are the following two methods:
Method 1: By limiting a maximum downlink noise margin of line and channel parameters in a template bound to a user port, it is ensured that a downlink signal-to-noise ratio margin (Signal-to-noise ratio Margin, SNRM) in line connection parameters does not exceed the limit value when a port is in Showtime state, so that a line transmit power of the user port is reduced, power consumption of a line driver (Line Driver, LD) is reduced, and finally power consumption reduction of an xDSL subscriber board is achieved.
Method 2: According to an output power of a line driver of a user port, the minimum undistorted power supply voltage of the line driver is determined, so as to control an output of a power module of the line driver to meet power transmission in the power, thereby achieving the objective of reducing power consumption of the line driver.
The inventor finds that the prior art has at least the following problems:
(1) Although method 1 can reduce power consumption of an xDSL subscriber board, a transmit power is reduced to a very limited degree and line driver power transmission efficiency is very low. In addition, many modems on the live network cannot support the feature of limiting Max SNRM, and there is an interworking problem.
(2) Although method 2 can reduce a power consumption of an xDSL subscriber board, method 2 just passively optimizes a power supply voltage of a line driver according to an output power. Therefore, the power consumption is reduced to a limited degree. In addition, when a plurality of line drivers uses the same power supply, the power supply needs to meet requirements of power transmission of all the line drivers. As a result, it is very difficult to reduce a power supply voltage and a better energy saving effect cannot be achieved.